Process for treatment of leather with condensates of aminoplast-sulfonated phenolic compounds



United States Patent Int. Cl. C14c 3/20 US. Cl. 894.24 7 Claims ABSTRACTOF THE DISCLOSURE Leather is pretanned, tanned or retanned with a Watersoluble condensation product of 1) an insoluble prepolymer formed byreacting l to 4 moles of formaldehyde with one mole of urea at a pHbelow 4 and (2) 0.7 to 2 moles of a sulfonated phenolic compound permole of urea used in the prepolymer.

CROSS-REFERENCES TO OTHER APPLICATIONS This application is a divisionalapplication of Ser. No. 226,718, Sellet, filed Sept. 27, 1962, nowPatent No. 3,340,215.

The present invention relates to novel high molecular weight anioniccondensates and products prepared therefrom and a process for producingthe condensate and its related products. The invention also includes anovel method for the treatment of materials penetratable or porous innature with said condensates and its related products alone or incombination with water dispersible nouionic treating agents, saidmethods and products being of particular importance in the leathermaking process.

It is an object of the present invention to provide for novel watersoluble treating agents especially for porous or fibrous substrates. Itis a further object-to provide novel Water soluble treating agents whichwhen applied to porous or fibrous substrates bring about enhancedproperties of said substrates. It is a further object to provideproducts which are particularly useful in the leather making process. Itis another object of this invention to provide products which are usefulas dispersing agents, dye assistants, pretanning agents, tanning agentsand retanning agents. Another object of this invention is to provideprocedures for preparing said novel treating agents. A still furtherobject of this invention is to provide for improved leather, paper, andtextile treating agents which impart improved properties when applied tosaid substrates in such operations as pretanning, tanning, retanning,dyeing and pigment dispersing. A still further object is to provide fora water soluble treating agent that can impart water solubility tononionic materials which have poor water solubility. Other objects willbecome apparent from the detailed description given hereinafter. It isintended, however, that the detailed description and specific examplesdo not limit the invention but merely indicate preferred embodimentsthereof since various changes and modifications within the scope of theinvention will become apparent to those skilled in the art. 7

The above as well as other objects have been most unexpectedly andsuccessfully achieved in the following manner. I have prepared andutilized in the treatment of various substrates such as leather and inthe solubilization and dispersion of many materials, products of watersoluble condensates of high molecular weight resinous polymers of ureaand formaldehyde with a sulfonated phenolic compound such as thoseselected from the group consisting of sulfonated phenols, sulfonatedcresols, sulfonated xylenols and mixtures thereof. More particularly, my

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invention relates to water soluble anionic polymeric condensates andproducts produced therefrom, said condensate being produced bycondensing in an aqueous medium at temperatures of from about 70 toabout 102 C., a mixture composed of a (1) substantially water insolubleresinous prepolymers formed by reacting approximately 1 to 4 moles offormaldehyde with 1 mole of urea at pHs below 4, with (2) a solfonatedphenolic component containing approximately 0.7 to 2 moles per mole ofurea used in formulating the prepolymer, of a sulfonated phenoliccompound, said sulfonated phenolic component having a total hydrogen ionconcentration of from about 8% to 24%, calculated as weight percentsulfuric acid, based on the total weight of the sulfonated phenoliccomponent with the proviso that when the prepolymer is formed byutilizing one mole of formaldehyde per mole of urea, the total hydrogenion concentration of the component should be from about 12% to 24%,calculated as Weight percent sulfuric acid, based on the total weight ofthe component. This condensation reaction of the prepolymer and thesulfonated phenolic compound is carried out by reacting for a period oftime from the formation of a clear solution which indicates the initialcondensation stage, until about 4 hours after the formation of a clearsolution; By varying the heating time and the temperature of thecondensation reaction of the prepolymer and the sulfonated phenoliccompounds, the mole ratios of formaldehyde to urea in the prepolymer,the hydrogen ion concentration of the aqueous solution, the finalproperties of the condensate can be controlled so as to produce productshaving desired predetermined properties for use as tanning agents,pretanning agents, retanning agents, auxiliary tanning agents,dispersing or solubilizing agents. By utilizing this procedure, I havefound that condensates can be produced having controlled molecular sizesand weights depending upon the desired use of the condensate.

It has been found that through this condensation reaction, the degree ofpolymerization of the urea-formaldehyde resin and the sulfonatedphenolic compound can be controlled so as to produce a final condensatehaving predetermined characteristics and properties. If it is desired tostop the reaction at the initial or first stage of condensation, themixture of the water insoluble polymeric urea formaldehyde resin andsulfonated phenolic compound is heated to a temperature of from about 70to 102 C., preferably from about 83 to 85 C., until the formation of aclear solution, indicating the formation of a water soluble condensate.The condensation reaction can then be stopped by cooling this clearsolution to room temperature. The pH of the final product can beadjusted to various levels depending upon the desired use. If a higherpolymeric product is desired,'this clear solution is heated to atemperature of from about 70 to 102 0., preferably between 83 to 85C.,under the aforementioned conditions, for a predetermined period of time.Any desired degree of polymerization of this condensate may be producedby carrying out the original reaction of the substantially waterinsoluble urea-formaldehyde resin and the sulfonated phenolic compoundfor a prede: termined period of time after formation of the clearsolution and then stopping the polymerization reaction by cooling thecondensate to room temperature or below. The pH of this final productmay be adjusted to any desired level.

It has been found that products produced by the second polymerizationstage, i.e., carrying out the condensation reaction of the sulfonatedphenolic compound with the substantially water insolubleurea-formaldehyde prepolymer for a period of time after the formation ofthe clear solution until two hours after the formation of the clearsolution, as well as products of the first condensation stage, i.e.,where the condensation reaction is carried'out until the formation of aclear solution, are excellent pretanning agents, retanning agents,tanning agents and auxiliary tanning agents for preparing improvedleather products. For example the products prepared by the firstcondensation stage impart to leather outstanding light fastness,increased fullness, enhanced tensile strength and smooth grain. Thoseproducts have excellent penetratability into the leather. Also theseproducts can be successfully used in such diverse applications in thetanning industry as in the preparation of garments, shoes, gloves,suedes and mechanical leathers.

During the second condensation stage, heating may be stopped and theproduct cooled at anytime up to two hours after the formation of a clearsolution depending upon the degree of polymerization desired. This istrue since the tanning characteristics and other properties of thiscondensate vary depending upon the degree of polymerization. This isshown by the fact that if a pretanning agent, tanning agent, retanningagent, with good penetration is desired, it is preferred to stop thepolymerization reaction as soon as possible after the formation of theclear solution so that a low molecular product can be obtained. If apretanning agent, tanning agent, retanning agent is desired which willgive a tighter grain and increased bleach to the leather, then thecondensation should be continued, so as to obtain a higherpolymerization product, by heating at definite temperature levels forgenerally up to two hours. Hence by regulating the time and temperatureof condensation of the urea-formaldehyde prepolymers with the sulfonatedphenolic compounds, in accordance with this invention, one can controlthe final product so as to produce a product having the desired tanningproperties.

These new products impart improved properties to substrates other thanleather. For example, when applied as dye assistants, improved colorvalues and better leveling are obtained in many instances. The first andsecond condensation stage products also exhibit dispersing and/orsolubilizing properties.

In the treatment of a substrate such as leather, generally from about 5%to about 25% by weight of my products can be utilized based on theweight of the wet shaved leather. Amounts of over 25 by weight of thetreating agent can be used but generally utilizing such high amountsdoes not provide any increased beneficial tanning properties. Hence itis seldom necessary to utilize these products in amounts in excess of 25by weight.

It has been found that by heating this condensation product of aurea-formaldehyde resin with a sulfonated phenolic compound at atemperature of from about 70 to 102 C. for a period of from about two tofour hours after the formation of a clear solution, a third stagecondensation product forms which exhibits excellent dispersing and/orsolubilizing properties for water insoluble materials such as pitchformed during the paper making process, water insoluble dyes andpigments. This increase in the degree of polymerization of thecondensation product causes a reduction of its usefulness as a tanningand treating agent with a subsequent increase in its.dispersing and/orsolubilizing properties. This product has improved dispersing and/orsolubilizing properties due to the high molecular weight and size of thecondensate formed during this stage of condensation. During the thirdcondensation stage, heating can be stopped and the product cooled at anytimefrom two to four hours after the formation of the clear solutiondepending upon the exact degree of polymerization desired.

If desired, the third stage condensation product can be made from thefirst or secondstage condensation product by heating the product to atemperature of from about 70 to 102 C. and then carrying out thereaction for the desired period of time. On the other hand, the thirdstage polymerization product can be prepared directly by carrying outthe original condensation reaction of a urea-formaldehyde polymericresin with a sulfonated phenolic compound at a temperature of from about70 to about 102 C. for a period of from about 2 to 4 hours after theformation of the clear solution.

In order to achieve the desired properties and characteristics of theproducts produced by this invention, heating of the condensate ofurea-formaldehyde product with sulfonated phenolic compounds at theaforementioned acid values, at temperatures of about 70 to 102 C. shouldbe stopped at some time up to about 4 hours after the formation of theclear solution. It has been found that if heating is continued past thisperiod under the above conditions, the molecular weight of the polymerbecomes so great that the product loses to a great extent its beneficialtanning, treating and solubilizing properties. Eventually, if heatingunder these conditions is carried out for too long a time, a thick gelforms which becomes difiicult to solubilize or disperse in water.

Besides having the aforementioned beneficial dispersing properties, theproducts produced by the third condensation stage are useful as tanningagents, pretanning agents, retanning agents; and, although due to thehigh molecular weight of these products, they do not have the excellentpenetratability in the hides or leather as do the products of the firstor second condensation stages. By regulating the time and temperature ofcondensation of the sulfonated phenolic compound with the ureaformaldehyde prepolymer during the third stage of condensation, one cancontrol the molecular structure and size of the products produced duringthis stage. In this manner the final product can be regulated so thatthe dispersing and solubilizing properties can be increased while manyof the tanning properties of the final product are simultaneouslydecreased.

In accordance with this invention, the molecular structure and molecularsize and in turn the final properties of the products of each of thecondensation stages are further dependent on the various resinousprepolymers obtained by condensing urea and formaldehyde. Hence byvarying the mole ratio of formaldehyde to urea in preparing theprepolymers, the specific properties of the final condensation productsproduced by condensing the prepolymer with formaldehyde under theaforementioned conditions could be controlled. For example, a condensateobtained by condensing a resinous prepolymer produced by polymerizingone mole of formaldehyde and one mole of urea with an aqueous solutioncontaining sulfonated phenol having a hydrogen ion concentration of23.7% calculated as weight percent sulfuric acid for a period of aboutone-half hour after the formation of a clear solution, gave excellentgrain filling properties to leather when used in a leather tanningprocess. This product also produced in retanncd leather, tighter grain,and excellent surface feel besides providing an excellent bleach for theleather..This product showed a diminished degree of solubility in waterunder progressive dilution, as shown by the fact that a white sedimentformed when a water mixture containing 5% by weight of this product wasprepared. On the other hand, when a second product was prepared in thesame manner except that the prepolymer was prepared from two moles offormaldehyde and one mole of urea and the hydrogen ion concentration was8% by weight, a condensation product was produced that was indefinitelydilutable in water and had a greater solubility under lower acidicconditions than the first condensation product. This second condensationproduct, which was prepared from the prepolymer formed by condensing twomoles of formaldehyde to one mole of urea, when applied to leather in aretanning process gave better penetration into the leather and moreuniform fixation in the leather than the first condensation product. Thedifference in the tanning properties of the two condensates was shownbythe fact that the first condensation product produced greater graintightening in leather when utilized as a retanning agent, as well as agreater filling of the leather and a higher bleach etfect in the leatherthan the second condensation product. The excellent leather fillingproperties of the first condensation product is due to its lowsolubility under highly acidic conditions and its diminished solubilityin water under progressive dilution which allows this product to settleout of solution and fill the pores or grains of the leather. Theseproperties are not present in the second condensation product.

The use of a condensate of urea, formaldehyde and a sulfonated phenoliccompound as a tanning agent, is disclosed by US. Patent No. 1,841,840,Muller, Jan. 19, 1932; U.S. Patent No. 2,127,068, Muller, Aug. 16,-1938; French Patent No. 1,266,511, Guthke et a1. All of these patentsshow a condensate prepared by simultaneously reacting urea, formaldehydeand a sulfonated phenolic compound. By utilizing a precondensate of ureaand formaldehyde. it has been found that a great variety of productshaving different chemical and physical characteristics can be producedand that the characteristics and properties of these products can becontrolled through the many variations made possible by the method ofthis invention.

The sulfonated phenolic compound for use in reacting with theurea-formaldehyde polymeric resin can, in accordance withthis-invention, be any sulfonated aromatic compound containing at leastone phenolic hydroxy group such as phenol sulfonic acid, cresol sulfonicacid, resorcinol sulfonic acid, naphthol sulfonic acid, etc.

In producing the products of this invention, it is essential that theurea and the formaldehyde be reacted to form a high molecular weightpolymeric resin prior to reaction with the sulfonated phenolic compoundso as to be able to produce condensates having predetermined tanning anddispersing and/or solubilizing properties due to the controlledconditions of the reaction. The products of this invention all impartimproved filling, grain characteristics, bleach and light fastness aswell as other improved tanning properties to the hide or leather to betreated, as well as provide improved dispersing or solubilizing agentsfor dyes, pigments, pitch formed during the paper making process, etc.In the treatment of a substrate such as leather from about to about 25%of this product is utilized based upon the weight of wet shaved leather.The products of this invention are applied to leather in the form of anaqueous solution.

It is essential in order to obtain the desired substantially waterinsoluble resinous prepolymer, to subsequently produce the products ofthis invention, that the reaction of the formaldehyde and urea becarried out at a pH of below 4, preferably from 3.2 to 3.8 for a periodof time sufiicient to form a slurry or a precipitate. The reaction ofthe ureaand formaldehyde under acid conditions is exothermic and can becarried out, in accordance with this invention, without supplying anyexternal heat. Due to the fact that this reaction may be slow instarting, it is generally preferred to heat the urea and formaldehyde toa temperature of from 40 to 60 C. and then allow the exothermic reactionto set in. The temperature during this reaction should be maintained at75 C. to 100 C. Furthermore, in the production of polymeric resinousurea-formaldehyde reaction products, suflicient quantities of reactantsshould be used to provide the reaction mixture with a ratio of fromabout 1 to 4 moles of formaldehyde for each mole of urea employed. Underthese conditions, high molecular weight polymers are formed which appearas white precipitates or slurries.

The improved products of this invention are readily prepared from thesepreformed substantially water insoluble resinous prepolymers. Forexample, this is accomplished by adding these resinous prepolymers -to asulfonated phenolic component. The sulfonated phenolic component mayconsist only of the sulfonated phenolic compound or it may be composedof a water solution of the sulfonated phenolic compound. In some cases,the sulfonated phenolic component should contain a neutralizing agentsuch as the primary amines or strong alkalis which include sodiumhydroxide, potassium hydroxide, ammonium hydroxide, ammonia, etc. and aproper amount of water to adjust the hydrogen ion concentration of thesulfonated phenolic component to from about 8% to 24%, calculated asweight percent sulfuric acid, based on the total weight of thesulfonated phenolic component. In cases where the sulfonated phenoliccomponent is already at that aforementioned hydrogen ion concentration,it is not necessary to add the neutralizing agent. But generally thehydrogen ion concentration of the sulfonated phenolic component is toohigh due to the fact that residual sulfuric acid is present from thesulfonation reaction of the phenolic compound under acidic conditions,and water and neutralizing agent must be added to adjust the sulfonatedphenolic component to the proper concentration and acidity beforereacting with the prepolymer. The neutralizing agent may be added to thereaction medium after the prepolymer and the sulfonated phenoliccomponent have been mixed together and before reaction, to adjust thereaction medium to the aforementioned hydrogen ion concentration. Alsothe prepolymer itself may contain sufiicient neutralizing agent so thatwhen it is mixed with the sulfonated phenolic component, it will lowerthe hydrogen ion concentration of the mixture to the proper level. Butgenerally for better control it is better to adjust the hydrogen ionconcentration, before the addition of the prepolymer to the sulfonatedcomponent by incorporating the neutralizing agent in the sulfonatedphenolic component.

After adjusting the proper acid level, the mixture of the sulfonatedphenolic component and the resinous prepolymer are heated to atemperature of from about to 102 C., preferably from 80 to 100 C. Theseconditions are maintained for at least a period of time sulficient toconvert the white slurry or precipitate into a clear solution whichindicates that the initial condensation reaction is complete. Generallyat temperatures of from 83 to C., condensation runs smoothly and thefirst condensation reaction proceeds in about 15 to 30 minutes.

By carrying out the condensation reaction of the sulfonated phenoliccompound at a hydrogen ion concentration of 8% to 24%, calculated asweight percent of sulfuric acid based on the total weight of the aqueoussolution containing the sulfonated phenolic compound, the resinousprepolymer which is in the form of a white slurry is activated so thatit can condense with the sulfonated phenolic compound to form the watersoluble condensates of this invention. It has been found that during thereaction of the various resinous prepolymers produced by varying themolar ratios of formaldehyde and urea with the sulfonated phenoliccompound, the hydrogen ion concentration is of prime importance inactivating the prepolymer so that it can react with the sulfonatedphenolic compound to form a condensate. This is shown by the fact, thatit has been observed, that by utilizing resinous prepolymers made bypolymerizing about one mole of formaldehyde with one mole of urea, ahigher hydrogen ion concentration was required to activate thisprepolymer than in cases where a prepolymer was formed utilizing highermolar proportions of formaldehyde per mole of urea. In the former case,a hydrogen ion concentration of from about 12% to 24%, calculated asweight percent sulfuric acid based on the total weight of the aqueoussolution, is required to activate the prepolymer so that it can reactwith the sulfonated phenolic compound to form a condensate in accordancewith this invention.

The polymeric condensates of the urea formaldehyde polymeric resin andthe sulfonated phenolic compound may be applied by means of an aqueousbath, alone or in conjunction with other tanning agents, to leather.These condensates are adsorbed and absorbed by the leather from theaqueous bath under acidic conditions or under neutral conditions wherebythey react with the hide to impart the aforementioned beneficial tanningproperties to the leather. Hence the condensates of this invention canbe applied to leather or hides in their neutralized or acidic states.

The polymerization condensates of this invention also aid in thesubsequent fat liquoring operations. However, when emulsions ofsulfonated oils are utilized in the fat liquoring operations, the highmolecular weight of the tanning agent of this invention inhibits to someextent the progressive penetration and fixation of these fat liquoringagents within the hides by breaking these emulsions. In accordance withanother embodiment of this invention, I have found that by modifying thecondensate of a urea-formaldehyde resin with a sulfonated phenoliccompound, by adding from about 0.1 to 0.3 mole of urea for every mole ofthe sulfonated phenol compound after the reaction between theseurea-formaldehyde resins and the sulfonated phenol has reached the firststage of condensation, as indicated by the formation of a clearsolution, and heating to a temperature of from 70 to 100 C., preferablyfrom 80 to 85 'C., for about onehalf to three hours, a lower molecularweight tanning agent will be produced which will not subsequently breakthe emulsions of the sulfonated fatty oil type fat liquoring agents.These modified condensation products have all the excellent tanningproperties and treating properties of the higher molecular weightcondensates. Hence, these modified condensates can be used as pretanningagents, retanning agents, tanning agents and auxiliary tanning agentsfor preparing improved leather products in the same manner of the highermolecular weight condensates of this invention.

The phenomenon whereby a lower molecular weight condensate of aurea-formaldehyde resin with a sulfonated phenolic compound is producedwhen additional urea is added to the reaction mixture of the sulfonatedphenolic compound just after this first stage of condensation has beencompleted, as indicated by the formation of a clear solution, is notcompletely understood, however, it is believed that these results areattributable to the fact that the urea provides a stabilizing orblocking elfect and prevents further build-up of the condensate. Thereaction of the urea with the condensate is carried out by heating totemperatures of from about 70 to 100 C., preferably from about 70 to 85C. I have found that temperatures above 100 C. promote many sidereactions, which produce a poor final product. The temperature of thisreaction should be maintained for a period of from about one-half hourto about three hours, preferably about two hours, depending upon thedesired product.

The modified condensate of this invention greatly enhances the fatliquoring operations especially when sulfated oil systems are utilizedas fat liquoring agents. Treating leather with fat liquoring agents suchas fatty oils-oil systems are old and well known in the leather tanningart. Typical sulfated fatty oils which may be used in conjunction withtheir fatty oils to treat leather in conjunction with the condensates ofthis invention include sulfated neatsfoot oil, sulfated rice bran oil,sulfated sperm oil, sulfated fish oil, sulfated cod oil, sulfatedmoellon oil, sulfated vegetable oil, sulfated mineral oil, sulfatedcastor oil, etc. These oils systems generally have an S content rangingfrom 2 to by weight of the oil system. Other sulfated oils which areutilized in the fat liquoring process of hides and skins are disclosedin US. Patent No. 2,630,408, Lighthipe etal., Mar. 3, 1953.

These oils systems are applied to the leather to be treated in waterafter the leather usually has been tanned. In the fat liquoring processwhere sulfated oils-oil systems are used, generally from about 2% to 25%by weight of these oil systems are utilized based upon the weight of thetanned leather. Usually enough water is added to the system so that theweight of the water is at least 8 equal to the weight of the tannedleather to be treated by the fat liquoring agent.

The products of this invention impart improved properties to substratesother than leather. For example, when applied as dye assistants,improved color values and better leveling are obtained. These productscan be utilized as pigment dispersants and as pitch dispersants.

Another advantage of these products are that they can be used inconjunction with substantially water insoluble nonionic lubricants forleather which are hereinafter described, to solubilize this lubricant inwater. Another advantage of utilizing these lubricants in conjunctionwith the condensates of this invention in the tanning of leather is thatthis mixture provides, particularly with chrome tanned leather, improvedfilling and softening, increased light fastness and dense fiberstructure.

The lubricants which can be solubilized by means of the products of thisinvention and which, in conjunction with the products of this inventionprovide to leather the improved treating properties, are selected fromthe group consisting of compounds having the following formula:

in which R is a straight or branched chain carbocyclic or alkylsubstituent having from about 5 to 12 carbon atoms n is a number fromabout 1 to 9 and the total number of carbon atoms in the R substituentis at least equal to the number n. Typical examples of such compoundsinclude bis-(p-tertiary octyl phenol condensed with three moles ofethylene oxide) methane, bis-(p-tertiary octyl phenol condensed with 6moles of ethylene oxide) methane, bis-(p-nonyl phenol condensed with 9moles of ethylene oxide) and bis-(p-n-pentyl phenol condensed with 5moles of ethylene oxide) methane.

In the above formula, it is necessary that the total number of carbonatoms in the R substituent be at least equal to the total number ofethylene oxide units condensed on the ring which is designated by theletter n. A bisphenol condensate is produced which can be eithersubstantially water insoluble or substantially water dispersible due tothe balance of the hydrophilic ethylene oxide with the hydrophobicalkylene groups. These bisphenol compounds are old and well known.Typical methods of preparing ethylene oxide condensates of alkylbisphenols are disclosed in S.N. 753,606, Liebling et al., filed Aug. 7,1958, now US. 3,064,057, Liebling et al., Nov. 13, 1962 and US.2,499,363, De Groote et al., Mar. 7, 1950. These methods can be utilizedto prepare the ethylene oxide bisphenol or phenol compounds designatedabove which are utilized in conjunction with the products of thisinvention.

By utilizing the anionic condensates of this invention as solubilizingagents, these substantially water insoluble nonionic lubricants can beapplied to leather in the form of water solutions. In this manner, thesenonionic lubricants will be retained on the leather due to theirsubstantial insolubility in water whereas the anionic tanning agent ofthis invention will be also permanently fixed on the leather by means ofreacting with the leather. In preparing a water soluble mixture of theaforementioned lubricant and the condensate of this invention, thelubricating agent should constitute from about 1 to about 60% by weightof the total mixture so as to impart the aforementioned beneficialproperties to the leather. In the treatment of leather with the abovemixture, from about 5% to about 25 by weight of this mixture of theanionic condensate of this invention and the nonionic lubricant areutilized, based on the weight of the wet shaved leather.

In accordance with another embodiment of this invention, I have foundthat if the resinous prepolymer is prepared by utilizing in excess of 2moles of formaldehyde for each mole of urea, that is from about 2 molesto about 4 moles of formaldehyde per mole of urea, preferably from about4 moles of formaldehyde per mole of urea, a condensation product isproduced in any of the three condensation stages which contains activemethylol groups which can further condense with amino compoundscontaining at least one active hydrogen atom connected to the nitrogenatom or cationic aminoplast resins to produce amphoteric tanning agents.These amino compounds and cationic aminoplast resins can becharacterized as nitrogen containing compounds which, by reactionbetween the hydrogen of the amine with the hydrox yl of the anioniccondensate, condense to produce amphoteric condensates. These amphotericmaterials are useful in tanning, retanning and pretanning operations.They are especially useful in a pretanning operation when vegetableextracts are subsequently used as tanning agents to produce a fullvegetable tanned leather. These amphoteric condensates allow penetrationof vegetable extracts into the leather quickly and easily.

The cationic aminoplast resins are prepared by interreacting orcondensing an amino resin base with an aldehyde, preferably formaldehydeor a compound which liberates formaldehyde, such as paraformaldehyde,trioxane and hexamethylenetetramine to form free methylol groups andthen condensing or interacting product with anamino resin base in orderto block off the free or active methylol groups, in the manner describedin U.S. Patent No. 2,944,046, Sellet. The amino resin bases can becharacterized as low molecular weight nitrogen containing compoundswhich by reaction between the hydrogen of amine with aldehyde, formmethylol derivatives in monomeric or polymeric form.

Examples of amino resin bases which are condensed with the formaldehydeinclude dicyandiamide, guanidine, guanylurea, urea, thiourea, biuret,melamine, ammeline, ammelide, cyanuric acid, guanamines as well as theirmixtures and derivatives. The cationic aminoplast resins obtained aboveare generally characterized as cationic to various degrees, as watersoluble or water dispersible and preferably should have a long andunlimited shelf life, i.e., should not undergo physical or chemicalchange upon standing for long periods of time. Exemplary of thesecationic aminoplast resins which can be reacted with the reactivemethylol groupings directly linked to the nitrogen within thecondensates of this invention, are those described in British Patent No.777,827, June 26, 1957 and in US. Patent No. 2,944,046, Sellet, July 3,1960.

The cationic aminoplast resins are characterized by their excellentshelf life and stability. This results from the elimination of freemethylol groups of the resin by reaction with amino resin bases such asthose given above. Other useful cationic aminoplast resins are those setforth in US. Patent No. 2,567,238, Sellet et al., Sept. 11, 1951;2,690,434, Sellet et al., Sept. 28, 1954; 2,847,396, Sellet, Aug. 12,1958, i.e., the resins prepared in column 1, line 7l-to column 2, line15 and claim 5, and 2,852,490, Sellet et al., Sept. 16, 1958. The degreeof cationic activity in the aminoplast resin is shown by interreactionwith anionic materials and is related to the degree of polymerizationand molecular size. Aminoplast resins which are strongly cationic innature are the higher molecular weight resins having a high degree ofpolymerization. Aminoplast resins having a lesser degree of cationicactivity have lower molecular weights resulting from a lower degree ofpolymerization. Also, the presence of carbamide groups tends toreducethe degree of cationic activity.

Examples of amino compounds containing an active hydrogen atom connectedto the nitrogen atoms which can' be reacted with the anionic condensatesof this invention to produce the amphoteric resins includedicyandiamide, guanidine, guanylurea, urea, thiourea, biuret, melamine,ammeline, ammelide, cyanuric acid, guanamines, ethylene diamine', etc.

With regard to the preparation of the amphoteric condensate which can beapplied to leather substrates, the following is set forth.

Cationic aminoplast resins or amino compounds can be condensed with theanionic condensates of this invention which have free methylol groupsavailable for reaction with the reactive hydrogen of the cationicaminoplast resin or the amino compound. This can be accomplished bycondensing from about .02 to 2 moles of the cationic aminoplast resin orthe amino compound with one mole, based on the moles of urea utilized informulating the prepolymer, of the anionic condensate of this reaction.An excess of the cationic aminoplast resin or amino compound (threemoles) may be mixed with the anionic condensate of this invention andcarried in neutral form in the cationic product. The reaction betweenthe amino compound or the cationic aminoplast resin and the anioniccondensate of this invention is preferably carried out at temperaturesof from about 50 C. to 100 C. Also the time of the reaction will vary indifferent cases, the time being usually in the range of about 1 to 3hours. As well known, the time may be decreased by increasing thetemperature and vice versa. Generally heating for over 3 hours producesno further condensation. The pH of the reaction medium is preferablyneutral although it may be very slightly acid or very slightly alkaline,i.e., from pHs of from about 6.5 to 7.9.

The amphoteric condensates may be further reacted with formaldehyde ifdesired, preferably from about 1 to 4 moles of formaldehyde, so as tointroduce complementary methylol groups in the amphoteric condensateswhich promotes further polymerization and complexing with metal salts.This is especially advantageous when an amino compound is used. I

These new amphoteric condensates are specifically improved auxiliarytanning agents, tanning agent, pretanning agents, retanning agents andmay be used in treating leather in the same manner as the anioniccondensates. The multi-charged characteristics of these amphotericcondensates provide a quick and uniform penetration of the raw hide andleather. A pretanning operation thus performed not only enables quickpenetration of the amphoteric condensate into the hide or leather butalso enables a rapid penetration into the leather or hide of metal saltsand other tanning agents in subsequent operations. This rapidpenetration produces a more even distribution of the metal salts andother tanning. agents within the leather or hide. By such operation afull and tight leather is produced.

In the treatment of a substrate such as leather from about 5% to about25% of any amphoteric product can be utilized based on the weight of wetshaved leather. These amphoteric products can be applied to leather bymeans of an aqueous solution under acidic or neutral conditions.

By the term formaldehyde as used in the specification and claims, I meanany compound capable of liberating formaldehyde such asparaformaldehyde, trioxane, etc. While formalin, which is anapproximately 37% by weight aqueous solution of formaldehyde ispreferably employed, formaldehyde in any of its polymeric forms, as, forexample, paraformaldehyde, trioxane, etc., can be used.

For a fuller understanding of the present invention, reference is madeto the following examples which are given for the purposes ofillustration only and are no to be construed in a limiting sense.

EXAMPLE I The following example is directed to the preparation of atanning agent utilizing phenol sulfonic acid, urea and formaldehyde.

244.5 pounds (3.0 moles) of 37% by weight of a water solution offormaldehylde, pounds of urea (1.5 moles) and 1 pound of formic acidwere added under constant stirring to a kettle. The resultant mixturewas heated in the kettle to 100 C., said temperature being maintaineduntil the formation of a white slurry which indicated the formation of aurea formaldehyde polymeric resin. The mixture was cooled to 75 C. and amixture of 348 pounds of phenol sulfonic acid, said mixture having atotal acid value of 26.5 to 27.8% calculated as weight percent sulfuricacid based on the weight of the pure phenol sulfonic acid, and 100pounds of water were added to the kettle. Upon the addition of the waterand the phenol sulfonic acid, an exothermic reaction took place whereinthe temperature rose from 75 to 103 C. As soon as this temperature wasreached, the reaction mixture was cooled back to 75 C. and another 100pounds of water was added. The temperature of the reaction wasmaintained at 70 C. until the formation of clear solution whichindicated a condensation product of the sulfonated phenol with theurea-formaldehyde condensate had been produced. After the formation of aclear solution, heating was stopped and another 100 pounds of cold waterwere added to the product dropping the temperature to 35 C. The productwas neutralized by adding 158 pounds of ammonia. The pH of theneutralized solution was 7.5.

EXAMPLE II This example is directed to a mixture of a condensate of aureaformaldehyde resin with phenol sulfonic acid and para octylbisphenol condensed with six moles of ethylene oxide per hydroxy group.

To the neutralized and cooled product of Example I, there was addedunder stirring 46.4 pounds of the sodium salt of hydroxy sulfo methaneand 25 pounds of water. This mixture was slightly heated to atemperature of 40 C. After stirring for 20 minutes at this temperature,120 pounds of bis(para-octyl-phenol condensed with six moles of ethyleneoxide)methane was added to the mixture. The ethylene oxide condensateand the mixture were stirred for 15 minutes at this temperature. Thismixture was a clear solution. After stirring for this period, pounds ofhydroxy acetic acid was added so as to reduce the pH of the resultingmixture to about 3.5. The resulting mixture was a light straw coloredclear liquid.

EXAMPLE III This example is directed to the formation of a tanning agentby condensing sulfonated o-cresol with a ureaformaldehyde polymericresin.

244.5 pounds (3 moles) of 37% by weight water solution of formaldehyde,90 pounds (1.5 mole) of urea and 1 pound of formic acid were added underconstant stirring to a kettle. The mixture was then heated to 60 C. Assoon as this temperature was reached, an exothermic reaction set in andthe temperature of the mixture rose to 100 C. This temperature wasmaintained until the formation of a white slurry which indicated that aureaformaldehyde polymeric resin formed. After the formation of thewhite slurry, heating was stopped and the reaction was allowed to coolto 80 C. A mixture consisting of 576 pounds of ortho-cresol sulfonicacid, 100 pounds of water and 166 pounds of 30 B. caustic soda wereadded under stirring to the slurry while the slurry was maintained at atemperature of 80 C. This mixture had a total acidity of 27.5%,calculated as weight percent sulfuric acid based on the weight of thepure o-cresol sulfonate. After this addition, the temperature of thereaction media rose to 85 C. without heat being applied due to theexothermic reaction. After this period, the temperature of the reactionmedia fell to 72 C. and this temperature was maintained by slightheating until the formation of a clear reaction solution which indicatedthat the condensation product of the urea formaldehyde resin with cresolsulfonic acid had formed. After the formation of a clear solution, thecondensation prouct was neutralized with the additional 222 pounds of 40B. sodium hydroxide and cooled to about 35 C.

'12 by the addition of 200 pounds of cold tap water. Enough 40 B. sodiumhydroxide was added so as to regulate the pH of the clear solution toabout 7.5.

EXAMPLE IV This example is directed to the urea modified condensateproduct of ortho-cresol sulfonic acid condensed with a urea-formaldehyderesinous polymer.

To the clear solution of the neutralized product of Example HI there wasadded 30 lbs. of urea, said product being at a temperature of 70 C.After the addition of the urea, the temperature was raised to about 85C. by means of heating. This temperature was maintained for a period oftwo hours. After this period, the product which was a clear solution wasneutralized and cooled to 30 C. by the addition of 200 pounds of coldtap water and 222 pounds of 30 B. caustic soda. The pH of the resultantsolution was about 7.2.

EXAMPLE V The following example is directed to the preparation of atanning agent produced by condensing ortho cresol sulfonic acid with anurea formaldehyde condensate formed by utilizing a moleratio offormaldehyde to urea of 1 to 1.

81.5 pounds of 37% by weight of a water solution of formaldehyde, 60pounds of urea and one pound of 90% by weight of a water solution offormic acid were added, under constant stirring, to a kettle. Theresultant mixture was heated in the kettle to 60 C. As soon as thistemperature was reached, an exothermic reaction took place raising thetemperature to about C. This temperature was maintained while themixture formed a white slurry which indicated that polymerization wascomplete. After the formation of a white slurry, the kettle was cooledto 80 C. and a mixture consisting of 376 pounds of ortho cresol sulfonicacid and 50 pounds of water were added to the kettle. After the additionof water and ortho cresol sulfonate to the kettle, the contents wereheated to a temperature of from 80 to C. After about 5 minutes a clearsolution formed indicating that a condensation product of the sulfonatedcresol with urea-formaldehyde polymer had been produced. This clearsolution was further heated to a temperature of about 83 C. for a periodof 30 minutes. After this period, the reaction product was cooled to 35C. and this product was then neutralized by adding 385 pounds of 30 B.sodium hydroxide. The pH of the neutralized solution was 7.5%.

EXAMPLE VI The following example is directed to the preparation of atanning agent produced by condensing ortho cresol sulfonic acid with aurea formaldehyde condensate formed by utilizing a mole ratio offormaldehyde to urea of 4 to l.

326 pounds of 37% by weight of a water solution of formaldehyde, 60pounds of urea and one pound of by weight of a water solution of formicacid were added under constant stirring to a kettle. The resultantmixture was heated in the kettle to 60 C. As soon as this temperaturewas reached, an exothermic reaction took place raising the temperatureto about 87 C. This temperature was maintained until the mixture formeda white slurry which indicated that the polymerization was complete.After the formation of a white slurry, the mixture was cooled to 80 C.and a mixture consisting of 376 pounds of ortho cresol sulfonic acid,pounds of water and 166 pounds of 30 B. sodium hydroxide were added tothe kettle. After the addition of this mixture to the kettle, thecontents were heated to a temperature of from 80 to 85 C. After about 5minutes, a clear solution formed indicating that the condensationproduct of the sulfonated cresol with urea-formaldehyde polymer had beenproduced. This clear solution was further heated to a temperature ofabout 83 C. for a period of 2 hours. After this period, the reactionproduct was cooled to 35 C.

EXAMPLE v11 This example is directed to the preparation of an amphotericcondensate.

306 pounds of the solution produced in accordance with Example VI wasintroduced into a reaction kettle equipped with a jacket, stirred, and areflux condenser. This product was then heated to a temperature of about83 C. whereupon 168 pounds of dicyandiamide were then introduced intothe kettle, under constant stirring. After a period of one hour, 326pounds of 37% by Weight of a water solution of formaldehyde wereintroduced into the kettle, while maintaining the temperature at about83 C. After all of the 326 pounds of formaldehyde was introduced intothe kettle, the temperature of the kettle was raised to 95 C. Heatingwas continued at this temperature for a period of 4 hours. After thisperiod, heating was stopped and the solution containing the amphotericcondensate was cooled to room temperature.

EXAMPLE VIII The following example is directed to the preparation of anamphoteric tanning agent.

(A) Preparation of the anionic condensate 244.5 pounds of 37% by weightof a watersolution of formaldehyde, 90 pounds of urea, and 1 pound of90% by weight of a water solution of formic acid were added underconstant stirring to a kettle. The resultant mixture was heated in thekettle to 60 C. As soon as this temperature was reached, an exothermicreaction took place, raising the temperature to about 87C. Thistemperature was maintained until the mixture formed a white slurry whichindicated that polymerization was complete. After the formation of awhite slurry, the kettle was cooled to 80 C. and a mixture consisting of166 pounds of 30 B. caustic soda, 376 pounds of ortho cresol sulfonicacid and 100 pounds of water were added to the kettle. After theaddition of water and ortho cresol sulfonic acid to the kettle, thecontents were heated to a temperature of from 80 to 85 C. After about 5minutes, a clear solution formed which indicated that a condensationproduct of the sulfonated cresol with the urea formaldehyde polymer hadbeen produced. To this clear solution containing the condensate, 30pounds of urea were added. This urea and the condensate were furtherheated at a temperature of about 83 C. for a period of 2 hours. Afterthis period, the reaction product was cooled to 35 C. and this productwas then neutralized by adding 166 pounds of 30 B. caustic soda.

(B) Formation of amphoteric condensate A reaction product was preparedby adding the following ingredients to a reaction vessel and heating ata temperature of about 100 C. until a clear solution formed.

95.05 pounds of a lignosulfonate solution of about 50% solids(extraction product from the purification of cellulose in themanufacture of paper pulp containing lignin and other natural organicmaterials which are sulfonated) 15.78 pounds of water 13.3 pounds ofdicyandiamide.

To this clear solution there were added 25.86 pounds of 37% by weight ofa water solution of formaldehyde. The formaldehyde and the clearsolution were heated together for one hour at about 85 C. so as to forman cationic aminoplast resin. This cationic aminoplast resin was addedto the solution containing the urea modified anionic condensate. Uponaddition of this cationic resin, the mixture was heatedto a temperatureof 85 C. for a period of about 1 hour so as to condense the cationicresin with the anionic condensate to form the amphoteric condensate.After this period, the solution containing the amphoteric resin was thencooled to room temperature. The cooled product was partially neutralizedby adding 172 pounds of 30 B. sodium hydroxide. The pH of the partiallyneutralized solution was 4.0. To the partially neutralized solution, 40pounds of by weight of a water solution of hydroxy acetic acid wereadded to reduce the pH to 2.8.

EXAMPLE IX This example is directed to the preparation of an amphoterictanning agent.

1310 pounds of the condensate produced in accordance with Example VI and289- pounds of aminoplast resin produced in accordance with Example XIIof the United States Patent No. 2,944,046 were introduced into a reac-'tion vessel under constant stirring. This mixture was heated to atemperature of to C. This temperature was maintained for a period of onehour whereupon all of the anionic condensate reacted with the aminoplastresin forming the amphoteric resin. The solution containing theamphoteric resin was then cooled to room temperature.

EXAMPLE X This example is directed to the preparation of an amphoterictanning agent.

1310 pounds of the condensate solution produced in accordance withExample VI and 530 pounds of aminoplast resin produced in accordancewith Example 15 of United States Patent No. 2,944,046 were introducedinto a reaction vessel under constant stirring. This mixture was heatedto a temperature of about 80 C. This temperature was maintained for aperiod ofone hour whereupon all of the anionic condensate reacted withthe aminoplast resin forming the amphoteric resin. The solutioncontaining the amphoteric resin was then cooled to room temperature.

EXAMPLE XI This example is directed to the preparation of an amphoterictanning agent. 1310 pounds of the condensate solution produced inaccordance with Example VI and 265 pounds of the aminoplast resinproduced in accordance with Example 15 of the United States Patent No.2,944,046 were introduced into a reaction vessel under constantstirring. This mixture was heated to a tempera ture of about 80 C. Thistemperature was maintained for a period of one hour whereupon all of theanionic condensate reacted with the aminoplast resin forming theamphoteric resin. The solution containing the amphoteric resin was thencooled to room temperature.

EXAMPLE x11 This example illustrates a typical retanning procedure forchrome pretanned skins or hides, using the products of Examples Ithrough VII and IX through XI as retanning agents.

Each of the products of Examples I through VII and IX through XI wereapplied to leather which was treated in the following manner. d

pounds of chrome pretanned side leather which has been wrung, split, andshaved to weight was placed into a drum. The hides were neutralized inthe drum to a pH of approximately about 4.0 by adding sodiumbicarbonate. The hides were subsequently washed at temperature of F.with water for approximately fifteen minutes to remove shavings, salts,and residual surface acidity. After washing was completed, the hideswere then floated in a drum by adding approximately "100 pounds of waterat F.

Each of the products of Examples I through VII and IX through XI wereapplied to the leather hides in the following manner:

Approximately 12 pounds of one of the tanning solu-' tions prepared inaccordance with Examples I through VII and IX through XI were added tothe drum. The

floated hides were treated with the tanning solutions for a period ofabout 60 minutes. After this period, the drum was drained. Aftertreatment with the tanning solution, the leather was then prepared forfat liquoring. This was accomplished by washing the hides with water forapproximately minutes at about 125 F. After washing, the stock wasfloated by adding approximately 100 pounds of water at a temperature ofabout 125 F. to the drum. After the flotation, fat liquoring was carriedout by adding about -8 pounds of a sulfated sperm oil having a free oilcontent of about 45% by weight, an acid value of 41 to 50 based on theweight of the free oil, and about 8 pounds of water to the drum. After48 minutes, the drum was drained.

The leather produced by the above procedure was full and mellow having atight grain. The leather was bleached white and had good resistance todiscoloration upon exposure to light.

The solutions drained from the drum after the fat liquoring and tanningprocedures in each case were cloudy except in the case when thecondensate of Example IV was utilized. In the case of the condensate ofExample IV the solution, obtained after the retanning and the fatliquoring operations, was completely clear. This indicated that therewas complete absorption and absorption of the condensates of Example IVas well as the fat liquor by the hide so as to yield clear solution.This illustrates that by modifying the condensates in the manner ofExample 1V, better penetration of the tanning agent into the hide andfat liquoring of the pretanned hide was accomplished.

EXAMPLE XIII This example illustrates the application of the mixture ofExample II and the condensate of Example VII as pretanning agents usedprior to the application of basic chromium salts to skins or hides. Eachof the products of Examples 11 and VII were applied to leather which wastreated in the following manner:

Approximately 100 pounds of drained pickled cowhide which was limesplit, baited, pickled, and drained was placed in a drum which contained200 pounds of water, at a temperature of approximately 80 F. and 10pounds of sodium chloride.

Each of the products of Examples II and VII were applied to the cowhidein the following manner:

Approximately 10 pounds of one of the tanning solutions prepared inaccordance with Examples II or VII were added to the drum containing thecowhide and the cowhide was treated with the tanning solution for aperiod of about 1.5 hours. After this period, 8 pounds of basic chromiumsulfate (Tanolin R) dissolved in 3 gallons of water was added to thedrum. This basic chromium salt solution was added to the drum in twofeeds, 30 minutes apart. When all of the basic chromium salt was addedto the drum, the cowhide was drummed in the basic chromium salt solutionfor a period of 5 hours. After this period, the drum was rotated for anadditional hour. After rotation, the resulting leather was neutralizedwith willcient sodium bicarbonate to produce a pH of approximately 4.After the pH was adjusted, the drum was drained. The leather was thenfat liquored by means of the procedure described in Example XII.

The leather which was produced by utilizing the mixture of Example II asa pretanning agent before the application of the basic chromium salt hadan better over-all tightening of the fiber structure, a 'fuller, rounderand softer feel, and enhanced light fastness than the leather producedby utilizing the condensation product described in Example VII as apretanning agent before the application of basic chromium salt. On theother hand, there is a quicker and more complete penetration of thetanning agent into the leather which is produced by utilizing thecondensation product of Example VII as a pretanning agent. The leatherproduced by utilizing the condensation product of Example VII had anincreased over-all tensile 1 6 strength over the leather produced byutilizing the product of Example II as a pretanning agent.

EXAMPLE XIV This example illustrates the application of a condensatedescribed in Example VII in replacing vegetable extracts in theretannage of chromium pretanned hides or skins.

100 pounds of chromium pretanned leather which has been wrung, split,and shaved to weight were placed in a drum. The hides were neutralizedin the drum to a pH of approximately 4.5 by adding sodium bicarbonate.The hides were subsequently washed with water at about to F. forapproximately 50 minutes to remove shavings, salts, and residual surfaceacidity. After washing was completed, the hides were then floated in thedrum by adding approximately pounds of water. 40 pounds of the tanningsolution prepared in accordance with Example VHI was diluted withsufficient water so that the volume of the tanning agent and the waterwas equal to 50 pounds of water. This mixture was added to the drumcontaining the neutralized, washed and chromed pretanned hides. Thefloated hides were treated with the tanning solution for a period ofabout 60 minutes to insure practical and economical exhaustion of thetanning agent onto the hides. After treatment with the tanning solution,the leather was then prepared for fat liquor. This was accomplished inthe manner described by Example XII. The leather obtained by the aboveprocedure had a tight grain, a solidity in the bellies and flanks withinthe leather as well as the increased fullness. The leather retanned inthe manner of this example resembled in every way leather retanned withvegetable extracts.

Having described by invention what I claim as new and desire to secureby- Letters Patent is:

1. A process for treating leather which comprises applying to saidleather an aqueous composition of a water soluble condensate which isthe condensation product produced by reacting in an aqueous medium at atemperature of from about 70 to 102 C., a mixture consisting essentiallyof (a) a substantially water insoluble resinous prepolymer formed byreacting from about 1 to 4 moles of formaldehyde with one mole of urea,said reaction being carried out at a pH of below 4, and

(b) a sulfonated phenolic component containing from about 0.7 to 2 molesper mole of urea used in formu: lating said prepolymer, of at least onesulfonated phenolic compound selected from the group consisting ofphenol sulfonic acid, cresol sulfonic acid, xylenol sulfonic acid,resorcinol sulfonic acid and naphthol sulfonic acid,

said mixture having a hydrogen ion concentration of from about 8% to24%, calculated as weight percent sulfuric acid based on the weight ofsaid sulfonated phenolic component with the proviso that when saidprepolymer is formed using one mole of formaldehyde per mole of urea,the hydrogen ion concentration of said mixture is from about 12% to 24%based upon the weight of said sulfonated phenolic component, carryingout said reaction by maintaining the temperature of said mixture at fromabout 70 to 102 C. until the formation of a clear solution andthereafter continually maintaining the temperature of said clearsolution at from about 70 to 102 C. by heating for a period of fromabout 0 to 4 hours.

2. The process of claim 1 wherein said leather is chrome pretannedleather.

3. A process for treating leather which comprises applying to saidleather an aqueous composition of a Water soluble condensate which isthe condensation product produced by reacting in an aqueous medium at atemperature of from about 70 to 102 C., a mixture consisting essentiallyof (a) a substantially water insoluble resinous prepolymer formed byreacting from about 1 to 4 moles of formaldehyde with one mole of urea,said reaction being carried out at a pH of below 4, and

(b) a sulfonated phenolic component containing 0.7 to 2 moles per moleof urea used in formulating said prepolymer of at least one sulfonatedphenolic compound selected from the group consisting of phenol sulfonicacid, cresol sulfonic acid, xylenol sulfonic acid, resorcinol sulfonicacid and naphthol sulfonic acid,

said mixture having a hydrogen ion concentration of from 8% to 24%,calculated as weight percent sulfuric acid based on the weightof saidsulfonated phenolic component with the proviso that when said prepolymeris formed using one mole of formaldehyde per mole'of urea, the

hydrogen ionconcentration of said'mixture isfrom about 12% to 24% basedupon the weight of said sulfonated phenolic component, carrying out saidreaction by maintaining the temperature of said mixture at from about 70to 102 C. until the formation of a clear solution and thereaftercontinually maintaining the temperature of said clear solution at fromabout70 to 102 C. by heating for a period of to 2 hours after theformation of said clear solution.

4. A process for treating leather which comprises applying to saidleather an aqueous composition of a water soluble condensate which isthe condensation product produced by reacting in an aqueous medium at atemperature of from about 70 to 102 C., a mixture consisting essentiallyof (a) a substantially water insoluble resinous prepolymer formed byreacting from about 1.5 to 4 moles of formaldehyde with one mole ofurea, said reaction being carried out at a pH of below 4, and

(b) a sulphonated phenolic component containing 0.7

to 2 moles per mole of urea used in formulating said prepolymer, of atleast one sulfonated phenolic compound selected from the groupconsisting of phenol sulfonic acid, cresol sulfonic acid, xylenolsulfonic acid, resorcinol sulfonic acid and naphthol sulfonic acid, saidmixture having a hydrogen ion concentration of from about 8% to 24%,calculated as weight percent sulfuric acid based on the weight of saidsulfonated phenolic component, with the proviso that when aid prepolymeris formed using one mole of formaldehyde per mole of urea, the hydrogenion concentration of said mixture is from about 12% to 24 based upon theweight of said sulfonated phenolic component, carrying out said reactionby maintaining the temperature of said mixture at from about 70 to 102C. until the formation of a clear solution, adding from about 0.25 to0.5 mole of urea to said clear solution while maintaining thetemperature at from about 70 to 100 C., and thereafter continuing saidreaction for a period of from about 0.5 to 3 hours by maintaining thetemperature of said clear solution at from about 70 to 100 C.

5. The process for tanning and fat liquoring leather which comprises (I)applying to said leather an aqueous composition of a water solublecondensate which is the condensation product produced by reacting in anaqueous medium at a temperature of from about 70 to 102 C., a mixtureconsisting essentially of (a) a substantially water insoluble resinousprepolymer by reacting from about 1.5 to 4 moles of formaldehyde withone mole of urea, said reaction being carried out at a pH of below 4,and (b) a sulfonated phenolic component containing 0.7 to 2 moles permole of urea used in formulating said prepolymer, of at least onesulfonated phenolic compound selected from the group consisting ofphenol sulfonic acid, cresol sulfonic acid, xylenol sulfonic acid,resorcinol sulfonic acid and naphthol sulfonic acid, said mixture havinga hydrogen ion concentration of from about 8% to 24%, calculated asweight percent sulfuric acid based on the weight of said sulfonatedphenolic component, with the provisothat when said prepolymer is formedusing one mole of formaldehyde per mole of urea, the hydrogen ionconcentration of said mixture is from about 12% to 24% based upon theweight of said sulfonated phenolic component, carrying out said reactionby maintaining the temperature of said mixture at from about 70 to 102C. until the formation of a clear solution, adding from about 0.25 to0.5 mole of urea to said clear solution while maintaining thetemperature at from about 70 to C., and thereafter continuing saidreaction for a period of from about 0.5 to 3 hours by maintaining thetemperature of said clear solution at from about 70 to 100 C., andthereafter (II) treating said leather with a water emulsion containing2% to 45% by weight of a sulfated fatty oil in an oil. 6. A process fortreating leather which comprises applying to said leather a watersoluble composition of matter consisting essentially of (a) from about99% to 40% by weight of an aqueous composition of a water solublecondensate which is the condensation product produced by reacting in anaqueous medium at a temperature of from about 70 to 102 C., a mixturecomprising a substantially water insoluble resinous prepolymer formed byreacting at a pH below 4 from about 1 to 4 moles of formaldehyde withone mole of urea and an aqueous solution containing from about 0.7 to 2moles per mole of urea utilized in formulating said prepolymer of atleast one sulfonated phenolic compound selected from the groupconsisting of phenol sulfonic acid, cresol sulfonic acid, xylenolsulfonic acid, resorcinol sulfonic acid and naphthol sulfonic acid, saidmixture having a hydrogen ion concentration of from about 8% to 24%,calculated as weight percent of sulfuric acid based on the weight ofsaid aqueous solution with the proviso that when said prepolymer isformed using one mole of formaldehyde per mole of urea, the hydrogen ionconcentration of said mixture is from about 12% to 24% based upon theweight of said aqueous solution, carrying out said reaction bymaintaining the temperature of said mixture at from about 70 to 102 C.until the formation of a clear solution, thereafter continuallymaintaining the temperature of said clear solution at from about 70 to102 C. by heating for a period of from about 0 to 4 hours, and finallyneutralizing said solution to a pH of from about 6.4 to 7.9 after saidheating has been discontinued, and (b) from about 1% to about 60% byweight of a water insoluble condensate, said water insoluble condensateselected from the group consisting of:

and

R R R wherein R is selected from the group consisting of alkylsubstituents having from 5 to 12 carbon atoms, carbocyclic substituentshaving from 3 to 12 carbon atoms, n is a number from about 1 to 8, andthe total number of carbon atoms in the R substituent is at least equalto the number n.

7. The process for treating leather which comprises applying to saidleather a material which is an aqueous composition consistingessentially of an amphoteric condensate formed by reacting at atemperature of from about 50 to 100 C.,

(a) one mole of an anionic condensate, said anionic condensate beingproduced by reacting in an aqueous medium, at a temperature of fromabout 70 to 102 C., a mixture comprising a substantially water insolubleresinous prepolymer formed by reacting at a pH of below 4, about 2 to 4moles of formaldehyde with one mole of urea, and a sulfonated phenoliccomponent comprising from about 0.7 to 2 moles per mole of urea used informulating said prepolymer of at least one sulfonated phenolic compoundselected from the group consisting of phenol sulfonic acid, cresolsulfonic acid, xylenol sulfonic acid, resorcinol sulfonic acid andnaphthol sulfonic acid, said mixture having a hydrogen ion concentrationof from about 8% to 24%, calculated as weight percent sulfuric acidbased on the weight of said sulfonated phenolic component with theproviso that when said prepolymer is formed using one mole offormaldehyde per mole of urea, the hydrogen ion concentration of saidmixture is from about 12% to 24% based upon the weight of saidsulfonated phenolic component, carrying out said reaction by maintainingthe temperature of said mixture at from about 70 to 102 C. until theformation of a clear solution and thereafter continually maintaining thetemperature of said clear solution at from about 70 to 102 C. by heatingfor a period of from about to 4 hours, with (b) from about 0.02 to 2moles per mole of urea utilized in formulating the prepolymer, of atleast one material selected from the group consisting of dicyandiamide,guanidine, guanyulrea, urea, thiourea, biuret, melamine, ammeline,amme'lide, cyanuric acid ethylene diamine and a cationic aminoplastresin wherein free methylol groups have been inter-reacted with at leastone amino resin base selected from the group consisting ofdicyandiamide, guanidine, guanylurea, urea, thiourea, biuret, melamine,ammeline, ammelide, cyanuric acid and ethylene diamine to block saidmethylol groups with one mole, based on the moles of urea, utilized informulating said prepolymer, of said anionic condensate,

said reaction being carried out at a pH of from 6.5 to 7.9.

References Cited UNITED STATES PATENTS 3,340,215 9/1967 Sellet 260-294FOREIGN PATENTS 1,142,173 l/1963 Germany.

LEON D. ROSDOL, Primary Examiner MELVIN HALPERN, Assistant Examiner US.Cl. X.R.

